Reborn as the Most Useless Hero in History

[Western fantasy + slow-paced + slice of life + carefully crafted worldbuilding + war] After dying suddenly, I somehow reincarnated as the hero from the game world of my previous life. But it turned out I was a hero with utterly pathetic stats! Faced with false accusations and all kinds of powerful enemies, I decided I had to fight to stay alive!

(The protagonist isn't a self-sacrificing saint or a eunuch, and he's smart.)